ACTU could boycott unions inquiry

The head of the ACTU says the royal commission into trade unions should be shut down, otherwise it will consider a boycott.

The ACTU says it could boycott the royal commission into trade unions unless it's shut down. (AAP)

The ACTU is considering boycotting the royal commission into trade unions if the federal government doesn't shut down the inquiry over a Liberal Party conflict of interest.

ACTU secretary Dave Oliver on Thursday blasted Justice Dyson Heydon for agreeing to speak at a Liberal Party fundraiser, saying it's proof the inquiry is biased.

"If Tony Abbott doesn't shut it down, we'll consider what our involvement will be in the future," Mr Oliver told reporters.